High-Inductance Explosive Magnetic Generators with High Energy Multiplication

Abstract

One of the classic types of explosive-driven magnetic flux compression generators — helical coils — is studied. There are the largest number of publications about this type of generator — both by Soviet and American authors. The reasons for the instability of the high-inductance generators operation are analyzed.

Furthermore, high-inductance helical coils are attractive not only because of their capability of effective operation at the loads with comparatively high inductance (1.0 – 2µH) and resistance (10⁻⁴ – 10⁻²Ω), providing high energy multiplication ratio (from some hundreds up to one thousand and more), but because of their constructive simplicity.

The most important feature of these coils is generation of high electric fields in compressed volume. It is shown, that under the given initial conditions minimum voltages can be obtained using exponential law of inductance distribution with a variable index of an exponent. Serious attention was paid to the problem of obtaining stable reproducible results and to the studying of the coil amplifying characteristics under the similar transformations of all their dimensions. For this purpose the coils differing in diameters in relation 1:2:4:6 were studied, but all linear dimensions of the first three coils were strikingly alike.

Most thoroughly was studied the generator having the coil diameter of 24 cm and initial inductance of 300 µH, which always permits to get in the load: L _f = 0.34 µ H, R _f = 10⁻³ Ω, energy 5.5 MJ (the energy multiplication ratio — 220). The results of a series of the experiments performed with another helical coil with the energy multiplication ratio increased up 1300 are also given. The quantitative regularity of energy multiplication change of these coils by dimension variations is derived.